This dataset is the publicly available version of the dataset used in Hajny et al. (2023).  These data are time series collected with the Purdue University Airborne Laboratory for Atmospheric Research (ALAR).  Please reference the publication listed in the Dataverse for context as to the original use of these flight data.  

The combined metadata file provides flight specific information such as the calibration applied for each flight, the inlet lag time for the Picarro, etc.  

Calibration coefficients have the convention:    calibrated_data = (raw_data - offset)/slope

The Picarro underwent maintenance on 02/20/2015 (month, day, year) and on 05/03/2018.  As such, although calibration coefficients are generally stable over time, they differ after each of these periods.

In general, the Picarro inlet lag time was determined by timing the time it took from breathing in front of the inlets to seeing an instrument response.  If this was/could not be done, it is generally estimated by "aligning" the downwind plume and will be noted in the metadata file.  As transects involve going back and forth, any inlet lag will cause the plume to appear considerably disjointed as, e.g., passes heading E will place the plume too far W and passes heading W will place the plume too far E.  A lag can be chosen that best aligns this signals.  Alternatively the ascent and descent of a corkscrew spiral can be aligned as, given location and time do not change significantly, the boundary layer height should be approximately unchanged.

Given the Picarro clock is slightly fast, the inlet lag may increase over time if it is not reset before every flight.  Additionally, the plumbing of the Picarro has varied slightly over the years, which will also impact the Picarro inlet lag.

All flight data was interpolated or block averaged to 1 Hz to prepare them for these files.  Transit to/from the power plants was removed and any timestamps that are missing location, time, or concentration data for any reason are removed.  If any other data is missing or otherwise unusable, it is set to the value NA.  Lastly, to maintain the anonymity of the facilities while still providing a useful version of the dataset we have converted latitude and longitude from degrees to the Lambert Conformal Conic projection using the proj string "+proj=lcc +lat_0=Facility_latitude +lon_0=Facility_longitude +lat_1=33 +lat_2=45 +x_0=0 +y_0=0 +datum=WGS84 +units=m +no_defs".  This puts the location data on a gridded projection in meters with the location 0,0 being the facility location.

The columns in this dataset are:

Time_UTC - Coordinated Universal Time in seconds since 1/1/1904.
Time_local - Local time.  The difference between UTC and local time is provided in the metadata and will vary depending on region and daylight savings.  In seconds since 1/1/1904.
Y_distance - Location data from the GPS system (-90 to 90) in degrees converted to the Lambert Conformal Conic grid.  This conversion makes this the distance from the facility (location 0,0) in meters.
X_distance - Location data from the GPS system (-180 to 180) in degrees converted to the Lambert Conformal Conic grid.  This conversion makes this the distance from the facility (location 0,0) in meters.
heightabvground_m - Elevation above ground calculated as HeightAbvMSL_m (from the GPS) - elevation data.  The United States Geological Survey digital elevation model’s Elevation Point Query Service (https://ned.usgs.gov/epqs/) was used to calculate elevations every 5 s during the flight track, which were then interpolated to 1Hz.  In meters.
P_stat - Air pressure reading from the four static ports on the BAT probe (absolute pressure) in mbar.
TempFUST_STAT - Fast Ultra Sensitive Thermocouple temperature after removing ramrise in K.
Tprime - MicroBead thermistor temperature after removing ramrise in K.
w_spd - Computed wind speed in m/s.
w_dir - Computed direction from which the wind is coming in degrees.
CO2_dry_cal - Concentration of CO2 after correcting for H2O and calibrating (calibration scale X2019), excluding calibration data in ppm.
CH4_dry_cal - Concentration of CH4 after correcting for H2O and calibrating(calibration scale X2004A), excluding calibration data in ppm.
CO2_dry_cal_OS - Equivalent to CO2_dry_cal, but based on an older calibration scale (X2007) in ppm.
CH4_dry_cal_OS - Equivalent to CH4_dry_cal, but based on an older calibration scale (X2004) in ppm.

There is additionally a file with the summary variables from each individual flight that were used in the multilinear regression discussed in Hajny et al. (2023).  These include most of the variables in Table S4 of the SI with others being calculated from a combination of terms available in this file.

If you wish to use this dataset please contact the authors as there is complementary data that may be of use to you. We are always happy to collaborate. Contact information for the authors is:

Kris Hajny: kristian.hajny@stonybrook.edu
Paul Shepson: paul.shepson@stonybrook.edu




